Alarm ciruit

ABSTRACT

A relay circuit, in combination with malfunction controls of a domestic heating system (oil burner) energized by a standard primary control whereby on a malfunction such as low water level, in addition to the shutoff of the oil burner, an alarm circuit is operated for an aural or visual signal.

I United States Patent 1 3,614,278

[72] Inventor Charles J. Di Noto, Jr. [56] References Cited.

103 West Passaic Ave., Rutherford, NJ. UNITED STATES PATENTS 070702,274,177 2/1942 Wilson 431/71 X [211 PP 17,769 2 297 821 10 1942 hFiled Mar. 9,1970 W empner 431/15 [45] lamented Oct 19 1971 I PrimaryExaminer-Carroll B. Don'ty, Jr.

Attorney-Nathaniel Ely [54] ALARM CIRUIT 3 Claims, 1 Drawing Fig.

[52] US. Cl 431/16, ABSTRACT: A relay circuit, in combination withmalfunction 431/69, 126/351, 126/388, 122/504.2 controls of a domesticheating system (oil burner) energized [51] Int. Cl. F23n 5/24 by astandard primary control whereby on a malfunction such [50] Field ofSearch 431/14, 15, as low water level, in addition to the shutoff of theoil burner,

16, 69, 71; 126/388, 374, 351; 122/5042 an alarm circuit is operated foran aural or visual signal.

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No.2 I06 I07 (LEFT) INVENTOR. Charles J.DiNOI0,Jr.

A NEY.

ALARM cmurr BACKGROUND OF THE INVENTION In domestic heating systems suchas those utilizing the typical oil burner for low-pressure steamgeneration, the oil burner is responsive to heat demands of a roomthermostat or a hot water thermostat in the domestic hot water system.

The steam generated in the furnace is distributed by suitable piping toindividual room radiators and when a sufficient temperature is reachedas set on the room thermostat, or a sufficiently high temperature isreached in the domestic hot water system, the oil burner controls arecut off.

With such systems, a primary control is provided for the interconnectionbetween the house current 120-240 volts), the oil burner motor, theignition device, the heat demand thermostats, and the malfunctioncontrols of the low-water sensor, the excessive pressure sensor and suchother sensors as may be provided.

It is obvious, in the case of the low water sensor, that the burnermotor be shut off promptly if there is insufficient water in the furnacefor if the furnace ran without water, it would not only damage thefurnace, but also due to the lack of generation of enough steam, theroom temperature would not satisfy the preset room temperaturethermostat and the burner motor would run without the typical cutout.

In addition to the above low water and excess pressure sensors thatoperate through the primary control, it is common to provide a stacktemperature sensor. This also works through relays in the standardprimary control in a manner such that fuel failures or unusual startingdelays due, for example, to ignition failure, also will shut off theburner motor. However, in this case, the heat demand thermostat willnot, by itself, restart the burner. Usually some reset button isprovided in the primary control which requires the operator to come tothe primary control, which is mounted in the chimney stack near thefurnace, to check out and correct the malfunction, and then to reset thestarting circuit.

It is apparent that in the usual malfunction, the homeowner will notknow of the event until the house becomes exceedingly cold. If a burnerdoesnt start, there is no evidence other than that the temperaturecontinues to drop. By the time it has reached a sufficiently low degree,which which might not be noticed by the homeowner in a warm bed, thehouse may be objectionably, and possibly dangerously cold.

I have now observed that the standard primary controls, such as thatmanufactured under the name Protectorelay by Minneapolis-HoneywellCompany, and particularly Model No. RAI 17A, can be interconnected to asupplemental alarm circuit in a manner to instantaneously report afailure of low water, excess pressure, or burner failure due to ignitionor fuel failure, the result of which is the failure to promptly raisethe stack temperature on heat demand.

By utilizing the standard primary control I add only a simple relaycontrol box containing two relays, a transformer and an alarm such as abell. The new control box is connected into the house current (1 -220volts) and across the primary control safety switch which can beutilized to give a low-voltage current. By the use of a high-impedancecoil relay in the low-voltage circuit, the opening of the safety switchwill not disturb the operation of other relays in the primary control.The necessary energy response, however, can be used to actuate thealarm.

The alarm itself is wired as by simple bell wire to the control box andis located at a convenient place in the house as near the cellar stairs,in the kitchen or other place where its operation is bound to benoticed. It will be understood that as soon as the malfunction iscorrected, the alarm is deenergized.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a diagrammatic sketch ofan alarm circuit, in accordance with my invention, shown interconnectedto a primary control for a domestic oil burner heating system primarilyto produce steam.

DESCRIPTION OF PREFERRED EMBODIMENT In a typical domestic steam-heatingsystem using oil for fuel, there are certain standard elements includingthe oil burner assembly A including the burner, the motor and theigniter. The standard primary control is represented at B having a stacktemperature sensor B which is mechanically attached to relays in theprimary control but projects into the chimney stack. Box C represents astandard junction box for the lowwater cutoff sensor and for thepressure-responsive sensor. A room thermostat is shown at D.

The primary control B is nonnally interconnected by lines 14-16-18 withthe room thermostat D. The primary control is also connected to thehouse current (I20-240 volts) through lines 10-12. As shown, however,this is usually accomplished through junction box C with line 10 goingthrough junction box C with line 10 going through the sensor inlow-water cutoff 20 and thence through the sensor in pressure control 24and out through line 26 to terminal 101. The other house current line12, through line 28 goes to terminal 102. This will energize the primaryof transformer 103 at all times.

With a standard primary control of the aforementioned Protectorelaytype, there are several relays to perform seriatim operations concernedwith the operation of an oil burner assembly. As described by themanufacturer, contacts 106 and 107, designated cold contacts, arenormally in closed position when the burner is idle and contact 108designated a hot contact, is open, the safety switch I05 is closed andboth relays 98 and 99 are deenergized. Relay 98 is mechanically linkedto contact switches 109, I10 and 111 as well as ignition switch 115. Ina similar manner, relay 99 is mechanically linked to contact switches112, I13, 1 14 and burner motor switch 116.

When the thermostat D calls for heatv by closing its contacts 14 and 16,the relay 98 becomes energized through the secondary of the transformer117, the closed safety switch 105, the hot contacts 106 and 107, and thesafety switch heater 90.

This, in turn, will not only close contacts 109, 110, and 111 but willclose contact 115 bringing on ignition through the house current circuit101, terminal 104, line 56 in which is the typical igniter transformerand line 52 to the terminal 102.

A split second later, relay 99 is energized through line 111A, safetyswitch 105, secondary of transformer 117, line 14, thermostat D, line16, heater and. contacts 109 (or 110) back to contact 111. Contacts 112,113, 114 and burner switch 116 are thus closed starting the motorthrough terminal 103.

When the temperature in the stack rises, the curved spring in stacksensor B expands moving the arm linkage to contacts 107 and 106,breaking them in that order, thereby deenergizing relay coil 98 which inturn breaks contacts 109-110-111- 115-, turning off ignition.

As the temperature continues to rise in the stack, contact 108 closesunder further movement of the sensor B and as the current then flowsthrough the contacts it ceases to flow through heater 90 of the safetyswitch 105.

Thus the system is in the run position with relay coil 99 ac tivated andcontacts 112-113-114-11I6 are closed with the burner motor running untilthermostat D is satisfied.

NEW ELEMENT In accordance with my invention, I provide an alarm circuitin control box 40. A terminal strip 42 is used to facilitateconnections. It also includes relay 44, relay 46, transformer 48 andalarm 50. The alarm 50, as previously noted, may be mounted at a remotepoint and need not be mounted withing the control box 40.

These elements are interconnected as follows:

Terminal 1 serves as a junction for the connection of the house currentpower source 10, through line 108, with the primary of transformer 48through line 74.

Terminal 2 serves 2 serves as a junction for the connection of the housecurrent power source 12, through line 12A, with the other side of theprimary of transformer 48 through line 72.

Terminal 3 is a junction for the connection of the house current source10, through line 10A from the center tap between the low-water cutoffsensor 20 and the excess pressure sensor 24 and the operating coil ofrelay 44. The other side of the coil is interconnected to terminal 2.

The relay 44 is shown with the contacts closed as would be the case withno power on the system. During normal operation, however, the contactswould be open. If there is a malfunction of low water, the coil of relaywould become deenergized and hence the contacts would again move to theclosed position.

Terminal 4 serves as the junction for lines 58 and 36 connected to acontact of the relay switch of relay 44 and through line 64 to alarm 50.

Terminal 5 serves as the junction for line 60 interconnected to thesafety switch 105 in primary control B, and one side of the coil ofrelay 46.

Terminal 6 serves as the junction for line 62 interconnected to thesafety switch 105 in primary control B, and the other side of coil ofrelay 46.

Relay 46 is normally deenergized with the switch contacts open. Acontact of the switch of relay 46 as well as a contact of the switch ofrelay 44 are connected by line 34 and line 32 through line 30 with theside of the secondary winding of transformer 48. The coil of relay 46 isof high impedance as will be hereinafter explained.

Terminal 7 serves as the junction for line 66 interconnected to alarm 50and line 68 connected to the other side of the secondary winding oftransformer 48.

A remote alarm, not shown, may be connected, as is alarm 50, withterminals 4 and 7.

EXAMPLE OF OPERATION If the sensor in low-water control 20 opens due toan unsafe low-water condition, it will break the house current circuitto the primary control as it is in the circuit from line 10, through thecontrol 20 and line 26 to the primary control and returning through line28 and line 12. in addition, it will deenergize the coil of relay 44,the switch contacts will close, and through line 30 from the secondaryof transformer 48, line 32, line 36, line 58, line 64, alarm 50, line66, and line 68 to the secondary coil, the alarm is energized. It willbe noted that although the low-water control 20 breaks the power circuitto the primary control B and hence will stop the burner, it does notdiscontinue current to the primary of transformer 48 which is energizedby lines B and 12A.

An alarm would also be given, through the primary control operation dueto a lack of combustion as for failure of ignition or absence of fuel orsimilar reason after the thermostat D had called for heat.

This results from the failure of the stack sensor B to open contacts 106and 107 and close contacts 108. During a preset interval of aboutseconds, the current flows through heater 90 of the safety switch 105.The metallic strip that holds safety switch closed is thus warped toforce the contacts open thus breaking the current flow through relays 98and 99. This discontinues all power to the burner assembly.

It is essential that the coil of relay 46 be of high impedance for ifnot the opening of safety switch 105 would not discontinue the flow ofcurrent to relays 98 and 99.

The foregoing description, although drawn primarily to anoil-bumer-activated domestic steam-generating combination, can also beapplied, within the concept of the invention, to hot air or hot watersystems.

I claim:

1. In combination with an oil burner assembly for a domestic heatingsystem wherein said assembly includes a burner motor, an ignition systemand an oil valve, a heat demand thermostat, and a primary control forsaid oil burner assembly having means reactive to chimney stacktemperatures which means include a safety switch which discontinuesmotor operation on failure of prompt heating of the chimney stack onactivation of the heat demand thermostat, and wherein a low-water sensoris interconnected to a house current and said primary control such thaton occurrence of low water, the primary control also discontinues motoroperation, an alarm circuit including:

a. a transformer interconnected to the house current;

b. an alarm device activated by the transformer;

c. a low-voltage relay system including a high-impedance coil shuntedacross the safety switch of the primary control, and a switch in thealarm circuit activated by the coil on opening of said safety switch toactivate the alarm, said safety switch being opened by the stackresponsive means on failure of prompt heating of the chimney stack onnormal heat demand of the thermostat.

2. In the combination of claim 1, the added relay system including ahouse current activated coil and switch, wherein the coil is in circuitwith the house current and low-water sensor, and the switch is in thealarm circuit, such coil becoming deenergized on failure of thelow-water sensor and thus causing the switch to close and activate thealarm.

3. In the combination of claim 2, the added circuit of an ex cesspressure sensor in the house current, high-voltage relay circuit wherebyon opening of the excess pressure sensor on the occurrence of excesspressure, the primary control and the oil burner assembly aredeactivated.

1. In combination with an oil burner assembly for a domestic heatingsystem wherein said assembly includes a burner motor, an ignition systemand an oil valve, a heat demand thermostat, and a primary control forsaid oil burner assembly having means reactive to chimney stacktemperatures which means include a safety switch which discontinuesmotor operation on failure of prompt heating of the chimney stack onactivation of the heat demand thermostat, and wherein a low-water sensoris interconnected to a house current and said primary control such thaton occurrence of low water, the primary control also discontinues motoroperation, an alarm circuit including: a. a transformer interconnectedto the house current; b. an alarm device activated by the transformer;c. a low-voltage relay system including a high-impedance coil shuntedacross the safety switch of the primary control, and a switch in thealarm circuit activated by the coil on opening of said safety switch toactivate the alarm, said safety switch being opened by the stackresponsive means on failure of prompt heating of the chimney stack onnormal heat demand of the thermostat.
 2. In the combination of claim 1,the added relay system including a house current activated coil andswitch, wherein the coil is in circuit with the house current andlow-water sensor, and the switch is in the alarm circuit, such coilbecoming deenergized on failure of the low-water sensor and thus causingthe switch to close and activate the alarm.
 3. In the combination ofclaim 2, the added circuit of an excess pressure sensor in the housecurrent, high-voltage relay circuit whereby on opening of the excesspressure sensor on the occurrence of excess pressure, the primarycontrol and the oil burner assembly are deactivated.